From Leonard Wolf's The Annotated Frankenstien

The physician Erasmus Darwin (1731-1802), grandfather of the more famous evolutionist Charles Darwin, was one of the most distinguished scientists of his age. A friend of the Godwin family, Darwin, a zestful womanizer and an audacious stutterer, was capable of dominating any conversation despite his handicap. A corpulent man, Darwin gave sound advice to his contemporaries on diet. His famous prescription for the disease pallor et tremor a timore was "Opium. Wine. Food. Joy."

In the introduction to the 1831 edition of Frankenstein, Mary Shelley refers to the "experiments of Dr. Darwin . . . who preserved a piece of vermicelli in a glass case, till by some extraordinary means, it began to move with voluntary motion." It is a curious reference, which has been illuminated . . . by a personal communication from Darwin's biographer, Desmond King-Hele, who writes, "Mary Shelley's remarks can, I think, be regarded as recording a mixed-up remembrance by Byron and Shelley of what Darwin wrote in his first note to The Temple of Nature. It is entitled 'Spontaneous Vitality of Microscopic animals' . . . Darwin does refer to a 'paste composed of flour and water' in which 'the animalcules called eels' are seen in great abundance and gradually become larger, even in a 'sealed glass phial.' He also refers to the vorticelli coming to life after being dried. Put this together and stir it up, and you might arrive at Mary's report." Darwin's most famous works, The Zoonomia and The Temple of Nature, are treatises written in quite skillful if endless heroic couplets.